If you are not familiar with Iris borer, it can be a common ailment in MN iris. They are a moth larvae that is specific to the iris family. They start as eggs in the tall fronds mid summer and appear as tiny burn spots. As heat and humidity rise, they burrow from the leaves all the way down into the rhizome as they get larger and need more substance to feed off. They overwinter and emerge as a cutworm the next year and moths hatch around now while the cycle repeats. I have dealt with them a few times over the decades.
I somehow missed the cue in 2024, so last year I had a miserable summer with greens but not a single iris bloom. A treatment is to wait until cool temps in the fall. Then dig up what is left of healthy roots, toss away the rot (which is a true stench in iris) and then soak the rhizomes in a bleach/ water mix to kill off any remaining eggs or larvae. It was cumbersome with around 12 varieties in multiple spots. But if you do not hit every one, it is an epidemic that will come back to haunt. I chose the right time to get them back in the dirt with a month left that most showed new shoots before the frost came.
Cut to 2026. All are healthy and have come back from the breech. Smaller clumps and some smaller blooms. But they are all bright and vibrant. This one is a favorite I got years back with really dynamic contrast between the Ivory face and an almost champagne outer round of petals. Thought it was worth a share and a story.
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